I think the title of your question is a bit impossible to answer in the specific sense, but theoretically I would say: "zero".
Rather than saying "rich", I prefer to call it "building wealth". Having friends and family and other aspects of life are more important than just having a boat load of money. An example of this is paying for the vacation of adult children and their spouses. One can save a lot of money by not doing so, but many choose to do exactly that so relationships are built between the siblings and between the children and parents.
The key thing to understand is that building wealth is a behavior driven process that involves serving your fellow human extremely well. One aspect of that service is to invest in companies. Sure, the naysayers can point to various "lottery" winners, but for the bulk of us that simply will never happen.
So how does one become first generation wealthy? How does one, with no special connections, no rich relative become comfortable (or more) financially? About 60-80% of "wealthy" folks, at any given time, qualify as this first generation wealthy.
The answer starts with service. Whatever that first job is, save some, give some, and spend some. Yep giving, a decent portion of your income, should be part of your wealth building plan. Investing in companies is serving the community, the employees, those that purchase the product, and of course the business owners. In your own profession you should serve your "customers" to the best of your ability.
If you make french fries in your current profession, make the very best you can. If you are a police officer, serve the citizens to the best of your ability. Whatever. There is no reason you have to do your current job forever and the better the job you do currently the more likely more profitable opportunities will exist in the future.
In the question noted in your post my answer mentioned that one could accumulate a great deal of money by simply "smoking", or investing what a typical smoker spends on cigs. However, it never works like that. Some people accumulate 10k or so and use it to buy a fancy car and with the payments can no longer afford to invest. Same kind of thing with a house when the account gets to something like 50k.
However those that really understand this, and sometimes it takes time and maturity to get there, invest far more than the 170 or so per month. Those kind of people can build generational wealth.
The statistics of net worth and income are interesting to study that shows this bears out.